Electromagnetic-wave-transmitting filter and electromagnetic-wave-sensing device

Abstract

The disclosure has an object to restrain properties of a filter from declining in reducing the filter in size. A periodically structured filter includes a plural types of filters. At least one of the plural types of filters is structured so as to have an optical parameter or shape that changes perpendicular to the normal to the surface of that filter with a prescribed spatial regular pattern. At least one of filters of an identical type in each unit and at least one of units adjacent to that unit is adjacent.

What is claimed is: 
     
         1 . An electromagnetic-wave-transmitting filter including an array of units each including at least two types of filters, each type of filter transmitting electromagnetic waves of a different range of wavelengths or of a different polarizing direction in a selective manner,
 at least one of the plural types of filters being structured so as to have an optical parameter or shape that changes perpendicular to a normal to a surface of that filter with a prescribed spatial regular pattern, and   at least one of filters of an identical type in each unit and at least one of units adjacent to that unit being adjacent.   
     
     
         2 . The electromagnetic-wave-transmitting filter according to  claim 1 , wherein:
 each unit is an m×n array of filters, where m and n are positive numbers, but are not simultaneously equal to 1;   the filter structured in any of the units so as to have an optical parameter or shape that changes with a spatial regular pattern is located along a periphery of that unit; and   at least one of the plural types of the filters arranged along the periphery is identical to a type of a filter, adjacent to that filter, that is in at least one of units adjacent to a unit of interest.   
     
     
         3 . The electromagnetic-wave-transmitting filter according to  claim 2 , wherein of the filters in each unit, (1) those in each of which the optical parameter or shape changes with the spatial regular pattern with a larger period or (2) those in each of which linear segments that impart an optical parameter or shape that changes with a spatial regular pattern tilt with respect to a side of that filter by an angle close to an angle by which a diagonal of the filter tilts with respect to the side of the filter are preferentially located along a periphery of the unit. 
     
     
         4 . The electromagnetic-wave-transmitting filter according to  claim 2 , wherein:
 the filter structured in any of the units so as to have an optical parameter or shape that changes with a spatial regular pattern is located in a corner of that unit; and   at least one of the plural types of the filters located in the corners is identical to a type of a filter located in a corner, adjacent to that corner, of at least one of units adjacent to a unit of interest.   
     
     
         5 . The electromagnetic-wave-transmitting filter according to  claim 3 , wherein:
 the filter structured in any of the units so as to have an optical parameter or shape that changes with a spatial regular pattern is located in a corner of that unit; and   at least one of the plural types of the filters located in the corners is identical to a type of a filter located in a corner, adjacent to that corner, of at least one of units adjacent to a unit of interest.   
     
     
         6 . The electromagnetic-wave-transmitting filter according to  claim 1 , wherein segments that impart an optical parameter or shape that changes with a spatial regular pattern are formed linearly. 
     
     
         7 . The electromagnetic-wave-transmitting filter according to  claim 2 , wherein segments that impart an optical parameter or shape that changes with a spatial regular pattern are formed linearly. 
     
     
         8 . The electromagnetic-wave-transmitting filter according to  claim 3 , wherein segments that impart an optical parameter or shape that changes with a spatial regular pattern are formed linearly. 
     
     
         9 . The electromagnetic-wave-transmitting filter according to  claim 4 , wherein segments that impart an optical parameter or shape that changes with a spatial regular pattern are formed linearly. 
     
     
         10 . The electromagnetic-wave-transmitting filter according to  claim 5 , wherein segments that impart an optical parameter or shape that changes with a spatial regular pattern are formed linearly. 
     
     
         11 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 1 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         12 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 2 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         13 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 3 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         14 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 4 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         15 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 5 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         16 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 6 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         17 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 7 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         18 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 8 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         19 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 9 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.   
     
     
         20 . An electromagnetic-wave-sensing device that senses electromagnetic waves, comprising:
 the electromagnetic-wave-transmitting filter according to  claim 10 ; and   a plurality of conversion elements configured to convert electromagnetic waves transmitted by the electromagnetic-wave-transmitting filter to an electric signal,   wherein the electromagnetic-wave-transmitting filter includes filters disposed so as to face the respective conversion elements.